Depth-positioning apparatus for underwater research vehicles



Sept. 24, 1968 KwosHl TsUJl 3,402,687

DEPTH-POSITIONING APPARATUS FOR UNDERWATER RESEARCH VEHICLES Filed Sept. 14. 1967 4 Sheets-Sheet 1 Sept. 24, 1968 KIYOsI-II TsuJI 3,402,687

DEPTH-POSITIONKNG APPARATUS FOR UNDERWATER RESEARCH VEHICLES Filed Sept. 14, 1967 4 Sheets-Sheet 2 BUOYANCY FORCE FROM INFLATI-:D Buovs 3453s 56\ I' r.. l

, swITCI-I UNwINDINC WINCH I UNIT MoToR IN DRUMS "2O 8 22 1 VEHICLE I I L l l [ELECTRIC CLUTCH 52f-IovERRUNNING CLUTCII I 6% s a 58 MECHANICAL CONNECTION wINDINC DRUM I6 ELECTRICAL CONNECTION 44 ELECTRIC BRAKE F l g. 4

ELECTRIC 28 MOTOR 5 ELECTRIC UNWINDING DRUM 22 |2 TO VEHICLE CONTROLS Sept. 24, 1968 KwosHl TSUJ! 3,402,687

DEPTH-POSITIONI APPARATUS R UNDERWATER RES RCH VEHICL med sept. 14, 1967 4 sheets-sheet s WEIGHT OR ANCHOR sePt- 24, 1968 Kwosl-n TSUJI 3,402,537

DEPTH-POSITIONING APPARATUS FOR UNDERWATER RESEARCH VEHICLES Filed Sept. 14, 1967 4 Sheets-Sheet 4 Fig. /0

|o`o zo DEPTH m FEET uw .mmN Pmml ENOT DI. A .WUR N BE 5 .IFFU l MELOQ 2 S 2.. B B 8 VSANUW 2 F| B B T 2 l TT R B B F RMFO m mr w 6 s. msnm H E T \}G G MAR T E A G N 2 I N B B w F R m A D N RF m m l W N V P G A ,4 m m E STR T T D VCV' M A .l ONC R I UN R R TFA A A Y G G ESB UA Q T w M Q nlv 8 6 4 2 3 2 I 5 M 3 h @z ozz: 853mm wzazzn A 252;, OEE ao Avo mme A Saz; VoE 5Go United States Patent Oftce 3,402,687 Patented Sept. 24, 1968 3,402,687 DEP'HLPUSITINING APPARATUS FR UNDERWATER RESEARCH VEHICLES Kiyosh Tsuji, Camarillo, Calif., assignor to the United States of America as represented by the Secretary of the Navy Filed Sept. 14, 1967, Ser. No. 668,310 12 Claims. (Cl. 11d-16) ABSTRACT 0F THE DISCLSURE Apparatus for use with a positively buoyant underwater vehicle such as a manned observatory in order to lessen the internal power required to bring the vehicle to a desired depth. The concept utilizes the upward force created by the inflation of a buoyant member at a given depth in a body of water in order to unwind a cable from one drum of a rotating winch mounted on the vehicle. A second cable, tethered to a Weight resting on the ocean floor, is wound on a second drum by the rotation of the winch, and this winding action pulls the vehicle downwardly as the buoyant member rises to the surface.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Background of the invenlon The present invention is concerned with underwater observation and exploration. In particular, it relates to apparatus suilable for use in conjunction with manned Observatories of the type adapted for oceanographic studies of a relatively long-term nature.

The seas, and particularly the continental shelves, represent one of the worlds remaining frontiers of which man has relatively limited knowledge. Because of ready accessibility, the continental shelves have been investigated to a greater extent than the ocean depths. However, the equipment used in these investigations has been designed primarily for shortterm exploration, characterized by high mobility and allowing only limited observation of any single phenomenon.

The desirability of prolonging the time available for activity at selected underwater locations has been emphasized by current research such as the Sealab Project ofthe US, Navy. This work makes evident the importance ol information-collecting through visual observation and/ or photography of the underwater environment. The need consequently arises for an undersea observatory-laboratory designed to permit passive observation coupled with active experimentation over extended periods of time, either at a single location or at a variety of places within a selected area of limited extent.

In a copcnding U.S. patent application of Richard G. McCarty, lames G. Moldenhauer, and Jerry D. Stachiw, Ser. No. 566,694 tiled July 20, 1966, there is disclosed an underwater research vehicle which provides scientists and engineers with a comfortable housing while studying the marine environment or conducting experiments over extended periods at given sites. The vehicle therein described is in the form of a capsule fabricated of transparent plastic material, permitting panoramic visibility, and is of a size to accommodate a crew of two for a period of substantially ten days at a selected location. The individuals conducting the operation are not exposed to the liquid medium itself, and since it is contemplated that sea-level atmospheric conditions will be maintained within the capsule, elderly scientists and engineers may be accommodated without experiencing ill effects.

The above-described capsule comprises the buoyant en` velope of a pressure hull, this envelope being constructed to withstand external loads during handling above the water. and hydrostatic pressures within the water. Contained within this envelope is the apparatus necessary to maintain the desired atmospheric conditions, as well as housekeeping facilities and research instrumentation. Since there is no requirement for horizontal propulsion, conventional self-contained power supplies are utilized, these power supplies being capable of supplying suicient energy to operate an associated winch mechanism and thereby control the vertical positioning of the capsule. lt is contemplated that the capsule will be tethered to the ocean floor by a cable leading to the winch, and, as the cable is selectively wound on the winch, the capsule will be drawn down against its natural buoyancy. Positioning of the vehicle at any point in a water column from the surface to a depth on the order of 1,000' is thus possible. The positive buoyancy of such an edreobenthic maimed observatory causes it to exert a pull against its bottom anchor, thus providing stability against ocean currents, undersea waves, and movements of the occupants.

The concepts involved in the design and construction of a vehicle such as above described have a sound technical foundation which is verifiable in practice. Insofar as the power supply is concerned, conventional 12-Volt 200 amp-hr. storage batteries may be employed, and, for a pressure hull having an outside diameter of tcn feet, the power supply may comprise four layers of batteries with 22 batteries per layer, or 88 units in all. Although the average power requirement during a ten-day mission may approximate 80() watts, maximum or peak power output occurs during winch operation as the capsule descends, and may amount to nearly 5,000 watts over a l-hour descent period. lf it were not for this single factor, the number of batteries, and hence the overall size and Weight of the power supply, could bc drastically reduced, thereby simplifying design of the assembly and increasing the amount of space available for research equipment per se.

Summary of the invention The present concept is directed to apparatus for use with au underwater vehicle designed to reach a desired depth in the ocean or other body of water, and which utilizes the upward force of one or more buoyant members to create a downward force on the vehicle, thereby reducing the internal power requirements of the latter. In one embodiment, this upward force is initiated by inflation of a bag or balloon after the vehicle has reached a predetermined intermediate depth, and the buoyancy of this member activates a winch connected by a tethering cable to a weight or anchor on the ocean oor. As the winch operates, the cable is wound on the winch drum, drawing the vehicle downward.

One object of the present invention, therefore, is to provide means for utilizing the natural buoyancy of an inflatable member to aid in bringing a vehicle suoh as a manned observatory that is also positively buoyant to a desired depth in the ocean or other body of water.

A further object of the invention is to utilize the force developed by a buoyant member in order to operate a winch carried by an underwater vehicle, the operation of this winch acting to draw the positively buoyant vehicle downwardly as the buoyant member rises to the surface.

An additional object of the invention is to reduce the winching power requirements of an underwater vehicle designed to descend into the ocean depths by utilizing energy developed by the controlled ascent of one or more inflatable members carried by the positively buoyant vehicle and which are rendered buoyant when the vehicle has reached an intermediate point in its powered descent.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

Brief description of the drawings FIG. 1 is a partly schematic illustration of one form of depth-positioning apparatus designed in accordance with a preferred embodiment of the present invention, and utilizing `a pair of inflatable buoys;

FIG. 2 is a partly schematic view, in perspective, of one form of power generation and transmission equipment suitable for incorporation into the apparatus of FIG. 1;

FIG. 3 is an internal 'view of certain of the elements of FIG. 2 presented in schematic fashion in order to aid in an understanding of the manner in which the equipment functions;

FIG. 4 is a schematic diagram of the electrical and me chanical connections between certain of the components of the device set forth in FIGS, l, 2 and 3;

FIG. 5 is a diagrammatic representation of certtin elements of the apparatus of FIG. 1 and indicating the respective forces acting thereon when the invention assembly is in its intended environment;

FIG. 6 is a partly schematic view along the lines of FIG. 1 but illustrating a modied form of depth-positioning apparatus employing a single inflatable buoy;

FIG. 7 is a diagrammatic representation in the manner of FIG. 5 but bringing out the forces acting on the apparatus of FIG. 6 when the assembly is in its intended environment; and

FIGS. 8, 9 and 10 are graphs bringing out certain operational characteristics of the apparatus of FIG. 6 as a function of variations in the gear ratio R1."R2 between the winding and unwinding reels schematically shown in FIG. 7.

Description of the preferred embodiment In FIG. l of the drawings is illustrated an underwater vehicle of a type with which the present invention finds particular utility. This positively buoyant vehicle is in the form of a generally spherical capsule or pressure hull, generally identified by the reference numeral 10, intended to move in essentially vertical fashion through the ocean or other large body of water. inasmuch as the constructional details of such a capsule form no part of the present invention they will not be set forth herein, but reference is made to the mentioned copending application S.N. 566,694 for a discussion of one manner in which the unit may be fabricated. Purely as an example, the capsule 10 may comprise an edreobenthic manned observatory designed for underwater research over prolonged periods of time at a given site and capable of housing a crew of at least two individuals in a substantially oneatmosphere environment.

To bring a capsule such as shown in FIG. 1 from the ocean surface to a desired depth, considerable power is required to overcome the vehicles natural buoyancy. This power may, of course, be supplied through electrical connections to a surface vessel, but it has been found that an independent arrangement is `much to be preferred and yields increased flexibility of movement of the vehicle while at the same time freeing the surface vessel for other activity. On the other hand, a conventional self-contained power supply capable of bringing the vehicle to any considerable depth must of necessity be of relatively large size and weight. rIlhis detracts from the capsules ability to house the large amount of equipment necessary to carry out an extended research program, as well as to restrict the space assigned to housekeeping facilities for the crew members. Consequently, at the present time a rather unsatisfactory compromise between these requirements is necessary. Suitable self-contained power supplies such as batteries unfortunately feature a reduction of available power as a function of power drain.

lil

The present concept is directed toward reducing the internal power needed to bring about descent of such a vehicle when its self-contained power supply starts to run down by utilizing the natural buoyancy of one or more inllatable members to counteract the inherent buoyancy of the capsule. In one embodiment, a pair of inflatable bags or balloons are each filled from a source of compressed air or gas as soon as the vehicle has reached a predetermined depth under its own power. The resulting buoyancy of each bag acts to unwind a cable from la drum carried by the vehicle and to concurrently wind a further cable on a different drum. Inasmuch as the latter cable is tethered to a weight or anchor on the oor 0f the ocean or other body of water, the vehicle is drawn downwardly until such time as the inated bags reach the surface. With proper choice of values for the components involvedv` the force developed by the rising buoyant members will be sufficient to position the vehicle at thc proper depth to perform the research activity contemplated.

Referring again to FIG. l of the drawings, the capsule 10 is tethered by means of a cable 12 to a weight or anchor 14 resting on the floor of the body of water in which the capsule is immersed. Cable 12 is arranged to be wound on a drum 16 forming part of a winch assembly generally identiiied by the reference numeral 18. This winch assembly is securely attached to the lower portion of the capsule 1t] and moves as a unit therewith.

Also forming part of the winch assembly 18 is a pair of further drums 2() and 22 carried on opposite ends of a shaft 24, the latter shaft being concentric with the axis of rotation of the drum 16 on which the tethering cable 12 is wound. However, as will subsequently appear, the drum 16 is not mounted on shaft 24 but on a hollow sleeve (shown in FIG. 3) concentric with shaft 24. As illustrated, a cable 26 is wound on drum 20, and a cable 2S Wound on drum 22.

Attached to the free end of cable 26 is a container or cylinder 3() of pressurized gas, which gas, when released from the container by operation of a hydrostatic valve 32 or by manually-actuatable control means (not shown) within capsule 10, lills a bag or buoy 34. Initiation of gas flow into bag 34 occurs while the bag is in a collapsed condition adjacent drum 20, as shown by broken lines in the drawing. lt is intended that the hydrostatic valve 32 operate after the capsule l0 has descended from the surface to a point about twothirds of the total distance to the ocean floor or to its desired depth.

A second bag or buoy 36 is attached to the free end of cable 28, and is designed to be filled with gas from a cylinder 38 when hydrostatic valve 40 operates. This assembly is identical in all respects to the one previously described.

Forming part of the winch 18 is a motor and clutch assembly 42. the motor of this assembly acting to cause descent of the capsule I0 to a point where the hydrostatic valves 32 and 4G operate. Power for energization of the motor may be supplied from conventional sources cartied within capsule l0. When the motor is energized, the drum 16 rotates and winds cable 12 thereon, and, since the weight or anchor 14 is intended to remain stationary, the capsule lt] is drawn downwardly in the water column. A brake 44 holds the drum 16 against rotation and thus interrupts descent of the capsule whenever this is desirable. When brake 44 is holding drum 16 against rotation the motor of assembly 42 is normally not energized.

Ordinarily, the motor of assembly 42 would have to operate during the total capsule descent time, and power would be required to energize this motor for the full period necessary to bring the capsule to the ocean floor or to the depth desired for research activity. The power supplies necessary to do this would be of a size and weight such as to seriously detract from the vessels capability of accommodating equipment and personnel. The present concept is intended to obviate the requirement for a power supply of a capacity greater than that necessary to cause descent of the capsule to a point approximately two-thirds of the total vertical distance to be traveled.

It has been stated that the bags 34 and 36 in their unintlated state lie adjacent their respective drums 2t) and 22 as shown in broken lines in the drawing. When the capsule has descended to a predetermined depth (such, for example, as two-thirds of the total vertical distance to be traveled) due to the action of the motor forming part of assembly 42, the preset hydrostatic valves 32 and 40 are concurrently activated to initiate flow of gas from cylinders 30 and 38 into the respective bags 34 and 36. When the latter become buoyant, they rise toward the surface, unwinding the cables 26 and 28 from their respective drums and 22 and causing rotation of shaft 24.

Referring now to FIGS. 2 and 3 of the drawings, there is shown one mechanism by means of which the objec tives of the present disclosure may be achieved. As stated, the drums 20 and 22 are mounted on the opposite extremities of shaft 24, this shaft extending through a hollow sleeve 46 (FIG. 3) on which the drum 16 is carried. Brake 44 is also mounted on this hollow sleeve 46, the brake being preferably of the electric type controllable from within the capsule 10 by any suitable means (not shown).

Associated integrally with drum 16 is a gear 48 mounted on hollow sleeve 46 in a manner best Shown in FIG. 3. The gear 48 is provided with a plurality of axiallyprojecting pins 49 disposed equidistantly in essentially circumferential fashion, and which serve to support an annular outer race element 50 of an overrunning clutch 52 the inner race member 54 of which is carried on shaft 24. Clutch 52 may, for example, be of the conventional cam and roller type, as illustrated in FIG. 2.

An electric motor 56 drives the gear 48 through a worm S8. An electric clutch 6l), again controllable from within capsule l0 by any suitable means (not shown) is interposed between worm 58 and motor 56. The latter may be energized from a conventional power supply (not illustrated) carried within capsule 10.

Uperarion Initially, the capsule 10 is lloating on the surface of the ocean, with the cable l2 extending to the weight or anchor 14 on the ocean floor. The unwinding reels 20 and 22 are fully Wound, with the bags 34 and 36 uninilated and adjacent to their respective reels as shown in broken lines in FIG. 1. The capsule 10 is now winched to a predetermined depth by action of motor 56, this selected depth corresponding to approximately two-thirds of the total depth desired. The hydrostatic valves 32 and 40 then concurrently operate to permit inflation of bags 34 and 36 with gas from cylinders and 38, the amount of emitted gas being chosen such that the total effective buoyancy of bags 34 and 36, taken together, approximately matches the buoyancy of the capsule.

During this phase of capsule descent, the shaft 24 is at rest by virtue of the action of the overrunning clutch 52, which permits the outer race member to rotate with drum 16 while the inner race member 54 is stationary. Also, the electric clutch 60 (FIG. 2) is engaged so that motor 56 drives the worm 58, while the electric brake 44 is released to permit hollow shaft 46 to rotate. Consequently, motor 56 turns drum 16 to wind the cable 12 thereon and draw the capsule 10 downwardly against its natural buoyancy. It should be noted that the worm 58 is so designed as not to be self-locking.

At the selected depth, the bags 34 and 36 are inllated and become buoyant. In rising toward the surface, they unwind cable from their respective drums 20 and 22 and hence turn the shaft 24 on which the drums are carried. Due to the nature of the overrunning clutch 52, a positive engagement between the race elements 50 and S4 occurs, and the drum 16 is rotated by the buoyant force acting on the inflated bags. Such rotation of drum 16 results in continued descent of the capsule. During this phase the motor 56 can be deenergized through a manual con trol (not shown) or it can be power augmented automatically as a function of the rotation of shaft 24.

Reference is made to FIG. 4 of the drawings for the electrical and mechanical interrelationship of the components of FIGS. l through 3.

It is intended that the capsule 10 reach its desired depth at approximately the time the inllated bags 34 and 36 reach the surface, the cables 26 and 28 being of a length such as to permit such operation to occur. To retain the capsule at such location, the brake 44 is engaged and clutch 60 released. Of course, the capsule may be stopped by energization of the brake 44 at any desired depth until the bags 34 and 36 reach the surface. The inflated bags 34 and 36, on the ocean surface, may be retrieved if desired by a vessel, the cables 26 and 28 being provisioned to be automatically released from their respective drums 20 and 22 when fully extended inasmuch as they are no longer needed.

At the conclusion of the project or research activity, it is only necessary, in order to permit the capsule 10 to rise to the surface. to release the brake 44. The capsule 10 will now ascend due to its own inherent positive buoyr ancy, allowing the cable 12 to unwind from drum 16.

It is contemplated that certain safety arrangements will be incorporated into the disclosed assembly, but these have not been illustrated or described since suitable expedients will be readily' apparent to those skilled in the art to which the invention pertains. For example, il the capsules electric power should fail or the various switch controls malfunction, the clutch 60 and brake 44 are so designed as to automatically become disengaged to permit cable 12 to unwind from drum 16 as the capsule 10 ascends to the surface by virtue of its own buoyancy.

It has been mentioned that capsule l0 may be brought by its own internal power supply to a point approximately two-thirds of the total downward distance to be traveled in the water column. This can be accomplished if the radius of each of the reels or drums 20 and 22 is three times the radius of the reel or drum 16. Under such conditions, a three-to-two torque advantage results at the take-up reel 16 in terms of available versus required torque. when the bags 34 and 36 exert a buoyant force on their respective unwinding reels 2t) and 22. Thus, the take-up reel 16 is now being driven by the unwinding reels, and since (because of the ratio of their diameters) the unwinding reels spool out cable three times faster than the take-up reel winds cable, the capsule 10 will be winched the remaining one-third of the total desired depth and reach bottom just as the inflated bags reach ythe surface. For example, if the weight or anchor 14 is at a depth of 300 feet, inflation of bags 34 and 36 at a 20D-foot depth will result in the reels 20 and 22 releasing 360 feet of cable while winding reel 16 takes up feet of cable as the capsule descends to the 300- foot depth. At this point the bags 34 and 36 have reached the surface, as previously described.

In FIG. 5 of the drawings is illustrated a diagram of forces which may be present on the various components of the assembly of FIG. l when the device is submerged. Purely as an example, if B1 is the buoyancy of capsule 10 and B2 the total buoyancy of the two inilated bags 34 and 36 taken tog-ether, then with equal buoyancies 132/2 for the two buoys it is possible to set It has been stated that the respective radii of the windmg and unwinding reels is such that Then the total tension t2 on cables 26 and 28 due to the intlated bags 34 and 36 is The tension on the anchor cable 12 is 4 :Fan

The available torque T2 becomes T2=t2r2 5 This is 1.5 times greater than the required torque T1, since For a vehicle having au assumed capsule diameter of 5.5 its operational buoyancy can be trimmed or ballasted to be in the neighborhood of 750 lbs. A 'F50-pound buoyant force in sca water requires a buoy or balloon volume (total) of 11.7 cubic feet. As this buoy or balloon ascends c from the depth of say 200 feet to the surface, the gas d must expand by a factor of seven, so the final volume becomes 81.9 cubic feet at the surface. The 750-pound buoyancy at 200 feet then becomes 5,25() pounds just before breaking the surface. Consequently, each of the bags 34 and 36 incorporates means (not shown) for d spilling or discharging excess gas as it rises to the surface. The 11.7 cubic toot total volume of the bags 34 and 36 can be represented by one 2.82 ft. diameter sphere or two 2.25 ft. diameter spheres, but a natural-shape balloon should be designed with minimum circumferential stress 'A in the fabric for maximum freedom from splitting or rupture. As far as the cylinders 30 and 38 are concerned, they need not be of excessive size or weight, as one cubic foot of compressed air at 2,600 p.s.i. can provide p0 19.7 cubic feet at the 200 ft. arbitrary depth where intlation takes place.

ln IflG. 6 of the drawings is shown a modification of the device of FIG. 1 in which a single inflatable bag or balloon 62 is utilized in place of the two members 34 and 36 of FIG. l and with the unwinding cable 64 passing through a tubular passage 66 formed in the hull of capsule 10. In certain cases such a design may be desirable in order to help balance and align the upward buoyant forces with the downward pull from the weight li or anchor 14.

With only one inflatable clement being present, only one unvvinding drum 68 is required, this member being coupled by a gear assembly 70 to the winding drum 16, the latter being identical to the corresponding cornponent in FIG. 1. The shaft of drum 16 is controlled by a motor and brake assembly 72 in the same basic manner as in FIG. 1, while a clutch 74 permits the shaft of drum 68 to be disengaged from gear assembly 70 in a conventional manner. It is important to note that the drums or reels 16 and 68 in FIG. 6 are of the same diameter, and that the necessary winding-to-unwinding ratio is achieved by the choice of a l-to-3 gear ratio for the elements of assembly 70.

FIG. 7 is similar to FIG. 5 but illustrates the forces acting on the apparatus of FIG. 6. The buoyancy B1 of the capsule 10 is here equal to the buoyancy B2 of the single intlatable bag 62 of FIG. 6. The radius r1 of drum 16 is equal to the radius r2 of drum 68. However, the

radius of the gears of assembly 70 is such that n0 RI=3R2 The tension r2 in the cable 64 is and the tension t1 in the anchor cable is If F represents the force on the gear teeth in assembly 70, then TgztgrzzFRzzFRl/SzTl/S which is the torque at drum 68.

Therefore,

which is the torque available at drum 16.

Now,

Tlzllrlzltgrzzln which is the torque required at drum 16.

Then the torque available to bring about descent of the capsule 10 is greater than that required by a factor of 3 to 2 or a ratio of 1.5.

FIG. 8 is a graph bringing out the winch gear ratio (for FIG. 6) versus depth in feet at the point of inflation of the buoyant members for a winch drum with 30() feet of cable. However, the usable gear ratio for a given buoy- :mcy ratio is shown in FIG. 9, and must correspond to a torque ratio greater than one to be meaningful. In this figure, B1 is the trimmed buoyancy associated with the vehicle und its winding drum, and B2 the buoyancy on the unwinding drum of FIG. 5. By ascertaining the usable gear ratio from FIG. 9 it is possible to predetermine the minimum permissible starting depth for inflation of the member 62 of HG. 6. This is given by FIG. IG for a turque ratio of l.5 (available/required at winding drum 16|.

It should be borne in mind that the breaking strength ol the cable 64 limits the choice of buoyancy ratio, and as a practical mutter the selection of a buoyancy ratio of one and a gear ratio of three dictates a leve] of 2li() feet for intiation of the buoyancy member 62 of FIG. 6. or the corresponding members 34 and 36 of FIG. 1 for a contemplated research activity depth of 300l feet, und this yields a one-third saving in power over that required to drive a standard winch the full distance of 3:20 feet.

It will be recognized that many modifications and variations ot the present invention are possible in the light of the above teachings. For example, the number of iniiutnbie members is obviously not limited to two. and if additional devices are utilized their operation can be selectively sequenced if desired to more effectively extend the time during which u buoyant force is applied to the vehicle. iurtherinore, electrical switches in the form of solenoids can be substituted for the hydrostatic valves 32 Iand 4t), these controls being preferably interconnected so that release ot prcssuried gas from the cylinders 30 and 38 occurs simultaneously and chemical gas generators` can be substituted for pressurized gas. Still further, friction clutches may be utilized in place of the electric clutches 6!) and 74, and a friction-type brake substituted for its electric counterpart 44. lt is understood that various other ratios between si/es of corresponding cornponcnts are possible such as buoyancy ratios, gear ratios, reel ratios, ctc. by adjusting various parameters involved in the torque ratios and depth of initiation of the selfwinding feature. All of there expedicnts as well as others which will be apparent to those skilled in the art t0 which the invention relates are irteuded to be embraced within the scope of the appended claims.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. Apparatus for bringing about the descent of a vehicle capable of moving in an essentially' vertical direction through a column of water, said apparatus being carried by said vehicle as it moves downwardly from the surface to a predetermined depth, said apparatus comprising:

means tcthcring said vehicle to the bottom of said water column;

an inflatable member;

means for inllating said member following a movenient of said vehicle from the surface to a predetermined depth in said water column, as a result of which inflation said member is rendered buoyant; and

means for applying the upward force developed when said member is rendered buoyant to draw said vehicle downwardly against the action of said tethering means.

2. Apparatus in accordance with claim 1 in which said vehicle is in the form of a manned observatory.

3. Apparatus in accordance with claim 1 in which said means for applying the upward force developed when said member is rendered buoyant to draw said vehicle downwardly against the action of said tethering means includes a winch mounted on said vehicle, and in which said tethering means includes a first cable designed to be selectively wound on a first drum of said winch.

4. Apparatus in accordance with claim 3 in which said means for applying the upward force developed when said member is rendered buoyant to draw said vehicle downwardly against the action of said tethering means includes a further drum on said winch and a second cable connecting said buoyant member to said winch, said second cable being initially wound on the said further drum of said winch and being designed to be selectively unwound therefrom following inflation of said member.

5. Apparatus in accordance with claim 4 further including electrically-energized means forming part of said winch for bringing about a movement of said vehicle from the surface to a predetermined depth in said water column while said member remains uninliated.

6. Apparatus in accordance with claim S in which said means for inating said member following a movement of said vehicle from the surface to a predetermined depth in said water column includes a source of pressurized fluid and a hydrostatic valve connecting said source of pressurized fluid to said member, said valve being preset to open when said vehicle has descended to said predetermined depth.

`7. Apparatus in accordance with claim 6 in which movement of said vehicle from the surface to a predetermined depth in said water column while said member remains uninated is brought about by said electricallyenergized means acting to rotate said first drum of said winch and thereby winding thereon said first cable which forms part of said tethering means.

8. Apparatus in accordance with claim 7 in which inflation of said member by operation of said hydrostatic valve at said predetermined depth acts to bring about a rotation of the said further drum of said winch as said second cable unwinds therefrom while said buoyant member ascends in said water column.

9. Apparatus in accordance `with claim 8 further including an overrunning clutch disposed intermediate the two mentioned drums of said winch, rotation of said further drum following inflation of said buoyant member acting to bring about continued rotation of said first drum due to the operation of said clutch irrespective of the status of said electrically-energized means, whereby said vehicle continues to be drawn downwardly in said water column beyond the predetermined depth at which infiation of said member occurs.

10. Apparatus in accordance with claim 9 in which said vehicle is of generally spherical configuration with a vertically-oriented opening extending diametrically therethrough, said second cable being disposed in part within said opening.

11. Apparatus for bringing about the descent of a vehicle capable of moving in an essentially vertical direction through a column of water, said apparatus being carried by said vehicle as it moves downwardly from the surface to a predetermined depth, said apparatus comprising:

means tethering said vehicle to the bottom of said water column; a plurality of inatable members; means for inating said members in an essentially simultaneous fashion following a movement of said vehicle from the surface to a predetermined depth in said water column, as a result of which inflation said members are each rendered buoyant; and

means for applying the upward force developed when each of said members is rendered buoyant to draw said vehicle downwardly against the action of said tethering means.

12. Apparatus in accordance with claim 1l in which said lastmentioned means includes a winch having a plurality of drums one greater in number than the number of said infiatable members and all but one of which are arranged for concurrent rotation, a plurality of cables respectively connected to said plurality of inflatable members and initially respectively wound on all but said one of said plurality of dru-ms, and in which said tethering means includes a further cable designed to be wound on said one of said plurality of drums as a function of the uuwinding from their respective drums of the plurality of cables connected to the said inflatable members.

References Cited UNITED STATES PATENTS 8/1942 Hansen 114-16 X 12/1946 Newell 114-51 

